The objective of this project is to study the mechanisms involved in androgen mediated gene expression in the rat prostate and the seminal vesicle. A major group of secretory proteins in both organs is under androgen control. Both organs have a high concentration of poly(A ion)-mRNA which code for this group of secretory polypeptides. The structural genes for these polypeptides have been prepared and cloned using the "tailing method" and the plasmid pBR322. Many of the plasmids containing structural genes for these androgen dependent polypeptides have been identified by hybrid arrest translation. Large pieces of DNA containing the chromosomal gene for one of the seminal vesicle proteins (SVS IV) has been identified in a rat gene library and is presently being purified.